No time for rackspace math? Use the Rack Ruler instead. It’s a genuinely handy tape measure incremented in both rackspaces (red) and inches (black) down to 1/32” scale. Measuring 1” wide by 192” (16 feet) long, its Mylar-coated retracting steel tape is housed in a tough ABS case with a thumb lock and belt clip. This is a rugged tool, not a toy – precision made by Starrett®